1. Field of the Invention
The present invention relates to temperature compensated circuits and more particularly to temperature compensated, peak detector circuits.
2. Description of the Prior Art
Temperature compensation circuits often involve the use of a negative-temperature coefficient reverse-biased Zener diode in series with positive-temperature coefficient forward biased diodes. This common approach lacks precision of control.
Another prior art approach to temperature compensation is revealed in U.S. Pat. No. 4,101,841, entitled "Gain Control Circuit", issued July 18, 1978. In that prior art device, a circuit having a temperature dependence opposite to that of the gain control section is used to cancel the temperature dependence of the gain control section. This approach requires complex circuit matching to achieve precise stability.
In one type of prior art device for temperature compensation, typified in U.S. Pat. No. 3,392,342, entitled "Transistor Amplifier With Gain Stability", issued July 9, 1968, matched transistors having their base and collector electrodes connected are connected directly across the base-emitter junctions of one or more matched transistor amplifiers to provide gain stability. This approach involves the use of a current translator to impose one base-emitter voltage on another base-emitter for the purpose of maintaining stability of current gain. Although current gain stability is achieved in the face of temperature change, the collector currents of the input and amplifier transistors are only approximately equal, and, therefore, the device does not produce a value of output voltage equal to the peak value of input voltage, as is desirable in peak detector circuits.